Anthocyanin-Sensitized TiO₂ Nanoparticles for Phenazopyridine Photodegradation under Solar Simulated Light

Abstract

Pharmaceutical wastes are emerging as water contaminants. Like other organic contaminants, it is necessary to find safe and economic methods to remove them from the water. In this work, anthocyanin was used as a natural dye sensitizer for the wide band gap nanosize rutile TiO 2 . The TiO 2 /Anthocyanin particles were supported on activated carbon particle surfaces. The resulting composite, which was prepared and characterized by different methods, was then used as a catalyst in the photodegradation of phenazopyridine (a model pharmaceutical contaminant) under a solar simulated light. Depending on experimental conditions, up to 90% of the contaminant was mineralized leaving no new organic products in the reaction mixture. The results show the feasibility of using the activated carbon-supported TiO 2 /Anthocyanin photocatalyst for pharmaceutical contaminant removal in water. The natural dye anthocyanin readily sensitized the TiO 2 to visible light. The unsupported TiO 2 , with its nanosize particles, was not easy to recover by simple separation methods, while the activated carbon-supported catalyst was easily isolated by decantation after reaction cessation. Moreover, the recovered AC/TiO 2 catalyst could also be regenerated by adding fresh anthocyanin sensitizer after recovery for further reuse. Keeping the contaminant molecules closer to the catalytic sites by adsorption, the support also enhanced the efficiency of photocatalyst.

Nanoconjugation between Fungal Nanochitosan and Biosynthesized Selenium Nanoparticles with Hibiscus sabdariffa Extract for Effectual Control of Multidrug‐Resistant Bacteria

“…The HbE antibacterial powers were documented by several reports [43][44][45]; the calyx extracts were also proposed as effectual alternatives for controlling pathogens having multidrug resistance in animals and humans [42]. The high anthocyanin types and polyphenol contents in HbE (e.g., cyanidin-3-sambubioside, delphinidin-3-sambubioside, cyanidin-3-glucoside, and delphinidin-3-glucoside) were suggested to provide substantial antimicrobial, antioxidant, and anti-inflammatory actions in biological systems [43,45,46]. Additionally, the HbE antimicrobial action (in vitro) was ascribed to its flavonoid contents, which establish strong complexes with microbial cell walls, intensify their permeability, and lead to more penetration of extract and biocidal compounds into the cell [45].…”

Photosensitive Hybrid Nanostructured Materials: The Big Challenges for Sunlight Capture

“…As mentioned above, a current trend is a search for effective natural dyes extracted from plants or microorganisms. Recent reports on this kind of dyes as TiO 2 sensitizers include curcumin, a simple conjugated diketone found in turmeric (Curcuma longa) [70], and anthocyanin [71]. In several works, natural dyes are extracted from the species containing them, e.g., chlorophyll and flavonoid from parsley leaves and turmeric roots [72], chlorophyll and other pigments from cyanobacteria [73], anthocyanin-rich mixture from Vaccinium meridionale Swartz (Andean blueberry) [74], extract from Picramnia sellowii tree [75], or Chlorella pyrenoidosa, a green unicellular alga used as both sensitizer and biotemplate for Fe 3 O 4 -TiO 2 composites [76].…”

Photosensitization effect on visible-light-induced photocatalytic performance of $$\hbox {TiO}_{2}$$/chlorophyll and flavonoid nanostructures: kinetic and isotherm studies

“…Visible-light degradation of dyes and phenols over mesoporous titania prepared using anthocyanin from red radish has also been described by Yan et al [27]. Anthocyanin-sensitized TiO 2 nanoparticles for phenazopyridine photodegradation under solar simulated light have been prepared by Zyoud et al [28].…”